Fabric tester



Sept... 16, 1958 M E 2,851,878

FABRIC TESTER Filed NOV. 18, 1955 INVENTOR BELFORD D. MAULE ATTORNEY 2,851,878 Pateatea'se t. 16,1958

ice

United States Patent Oh zjsijiis maieiasien Belford D.Maule,"Naptileiin Mich. p Animation November is, i9 ss,-*seaai Nosswfisi I Cliiiin. or. 73 162 This invention relates to a portable device for testing fabric such as used on light aircraft, boats, etc. without removing the fabric therefrom.

In the use of fabric as a frame covering as used in airplanes, for example, the fabric will often weaken over a period of time due to exposure to rain, snow, sleet, etc. and. consequently the safety of the airplanes passengers may be in jeopardy if the fabric has weakened to the extent that it may tear while the airplane is in flight. Therefore, this invention pertains to a device which may be applied to the airplane fabric periodically ito test its strength and determine when the airplane should be recovered.

An object of this invention is to produce a fabric tester of compact and simple design which is readily portable.

Another object is to make a tester which is simple to operate and may be used by an inexperienced operator.

A further object is to produce a fabric tester which will give a direct reading of the strength of the fabric.

A still further object is to make a fabric tester which will test the fabric without inflicting injury thereto.

These and other objects of my invention will be apparent to those skilled in the art.

Referring to the drawings which disclose a particular embodiment of my invention:

Fig. 1 is an elevational view of the tester,

Fig. 2 is a vertical section,

Fig. 3 is an enlarged sectional view and Fig. 4 is an enlarged sectional view of a detail of construction.

My tester is of a size that may readily be held in one hand and comprises a handle 2 which is of a cylindrical tube-like shape and is open at each end. Adjacent to the lower end 4 of the handle and projecting inwardly is a press fitted shoulder ring 6. Mounted for sliding movement within the handle 2 is a plunger 8, also of a hollow tube-like configuration. However, the lower end of the plunger 8 is closed by a plug 10. A shoulder 12 is formed on the outer surface of the plunger 8 adjacent the upper end to act as a guide when the plunger is sliding within the handle 2. A stop ring 13 carried in a groove in the plunger 8 acts as a stop when ring 13 coacts with the handle shoulder ring 6 to limit the downward movement of the plunger 8.

A spring 14 is placed within plunger 8 and rests against the press fitted plug 10. Preferably the spring 14 in the unstressed condition is of less length then the length of the plunger 8 to enable the sleeve 16 to readily slip into the upper end of the plunger 8 and contacts the upper end of spring 14.

A cap 18 is press fitted attached to the upper end of handle 2 thereby sealing off this end of the handle after the parts are assembled. The upper end of sleeve 16 bears against the underside of cap 18 therein compressing spring 14 slightly.

It will therefore be observed that plunger 8 is slidably of the plunger tip,

M of the plunger has atip Zt) which contacts the fabric to be tested.

'10 T Pi'eferably the tip 20 is formed with'a slightly rounded end with smooth edges. 7

PlaEed on'theouter surface of plunger 8 are graduated indicia as at 22 which are read with respect to the lower end 4 of the handle as a reference line and the relationship of the area of the tip 20 and the graduation is such that a reading of 40, for example, that is when 40 is even with edge 4, indicates that the tip 20 is press:

ing on the fabric with 40 inch pounds. However, any 20 other desired scale may be used.

The tester operation is as follows:

As the strength of a new fabric is known there is available to the airplane inspector or mechanic a chart or standard from which the inspector may obtain data indicating the requisite strength of the fabric he desires to test. For instance, if it is desired to test the strength of the fabric of the airplane wings, the inspector would consult the standard data to determine what the safe testing strength of wing fabric should be. By way of example, suppose wing fabric should test 50 inch pounds. The inspector thereupon grips the handle 2 of the tester and places the tip 20 in contact with the wing fabric and forces the handle toward the tip 20. The plunger 8 remains stationary due to the support of the fabric and handle 2 slides over the plunger. If upon the coopera tion of the lower end 4 with the 50 mark on the plunger the tip 20 has not pierced the fabric the inspector knows that the fabric strength is sufiicient. The operation may be repeated at different points on the wing as many times as deemed necessary for a thorough inspection.

If it is desired to test the breaking point of the fabric the handle 2 need only be slowly forced toward the fabric while the operator watches the indicia as it passes end 4. By observing the reading as the tip 20 breaks through the fabric the breaking point is easily determined.

It is recognized that this device may be used. with other types of sheet material for testing purposes and it will be seen that I have constructed a testing device of a simple and economical design which is easily operated and will give an accurate reading even though performed by inexperienced personnel.

The rounded end of the tip 20 is one of the features of the invention when the tester is being used to test fabric with a doped surface as in the case of airplane surfaces. By rounding the end of the tip 20 as more clearly shown on Fig. 3 the initial pressure of the tip 20 will radially crack the brittle surface treatment of the fabric and substantially remove the same as a factor of resistance so that only the fabric offers resistance to the pressure of the tip 20.

I claim:

A fabric testing device characterized by being fabricated from lengths of tube sections comprising a hollow cylindrical tube section handle, a hollow cylindrical tube section plunger, an elongated cylindrical spacer, a plug at one end of said handle to close said end and pro vide an abutment for said spacer, said spacer being disposed in said handle and abutting said plug and having substantial clearance with the inner wall of said handle, the inner end of said plunger being open and said plunger telescoping within said handle and telescoping about said spacer with free sliding relationship, an annular groove in the outer surface of said plunger spaced from the inner end of said plunger, a shoulder ring in said groove and projecting slightly beyond the outer surface of the tube section from which the plunger is formed, the portion of said plunger between said groove and said inner end of saidplunger constituting a pilot and bearing portion between said plunger and handle, said handle having a groove on its inner surface adjacent its open end, a shoulder ring in said last groove and projecting slightly beyond the inner surface of thetube section from which said handle is formed, said rings having a free sliding fit with said-plunger and handle and abutting each other to limit the outward movement of said plunger, a plug closing the outer end of said plunger and having a rounded tip for engaging the fabric to be tested to break the surface treatment of the 4 fabric, a compression spring disposed in said plunger and abutting at one end the plug of said plunger and at the other end abutting the outer end of said spacer and indi'cia on said plunger between said tip and that portion of said plunger projecting beyond said handle.

References Cited in the file of this patent UNITED STATES PATENTS 1.571,3l0 Wilson Feb. 2, 1926 1,942,982 Schneider Jan. 9, 1934 2,421,449 Zuber June 3, 1947 2,522,544 Sayboth Sept. 19, 1950 2,588,387 Hughes Mar. 11, 1952 FOREIGN PATENTS 563,324 France Sept. 24, 1923 

